Minimally invasive surgical techniques have revolutionized cardiac surgery. Minimally invasive cardiac surgery enjoys the advantages of reduced morbidity, quicker recovery times, and improved cosmesis over conventional open-chest cardiac surgery. Recent advances in endoscopic instruments and percutaneous access to a patient's thoracic cavity have made minimally invasive surgery possible. Reduction in morbidity, lower cost, and reduced trauma has made minimally invasive surgery desirable.
However, many problems and controversies still surround the viability of minimally invasive cardiac surgical procedures. One such problem is the difficulties of locating and manipulating small vessels, arteries, or veins in a closed-chest, blind environment during, for example, a minimally invasive coronary artery bypass graft (CABG) procedure. The coronary arteries typically have a diameter in the range of between about 1 to 5 mm, and the coronary bypass graft vessels have a diameter on the order of about 1 to 4 mm for an arterial graft such as a thoracic artery, or about 4 to 8 mm for a vein graft such as a saphenous vein. Locating and manipulating these tiny vessels is sufficiently difficult in conventional open-chest cardiac surgical procedures, and is made substantially more difficult in closed-chest, less invasive mini-thoracotomy procedures and in minimally invasive endoscopic procedures where the cardiac surgeon may not be able to view these vessels directly. Endoscopic instruments are currently used by the cardiac surgeon to view the internal thoracic cavity during a minimally invasive surgical procedure, but the use of these instruments alone has inherent drawbacks. For example, it is often difficult to differentiate the often tiny coronary arteries or coronary bypass graft vessels from other surrounding vessels and tissues with the use of endoscopic instruments alone during a minimally invasive surgical procedure.
An alternative technique for performing minimally invasive cardiac surgery procedures, therefore, is needed which facilitates locating and manipulating vessels by illumination from within the vessels. The technique should employ transillumination of a coronary vessel or coronary bypass graft vessel with light at predetermined wavelengths that are not substantially absorbed by the vessel itself, blood, other bodily fluids, or surrounding tissues and the like. The surgical technique can be applied for example, to the following areas, although it is to be understood that the present invention is by no means limited to these specific cardiac surgery procedures: (1) dissecting a left (or right) internal thoracic artery (LITA or RITA) from the chest wall in preparation for anastomosing the LITA to a native coronary vessel in a CABG procedure; (2) locating the LITA graft in a CABG repeat procedure; (3) locating the coronary artery to which a coronary bypass graft vessel is to be anastomosed; and (4) harvesting a free graft vessel, such as a saphenous vein, in preparation for anastomosing the free graft vessel to a native coronary artery in a CABG procedure. Each of these procedures will be explained in greater detail hereinafter.
Transillumination within the body of a patient has been recognized for at least a century. As long ago as the mid-1800's, British physicians began detecting scrotal cancer by holding a lamp behind the testes and noting the shadows the tumors cast. See "Transillumination: Looking Right Through You," Science, Vol. 261, Jul. 30, 1993 at page 560. Transillumination of the stomach was reported as early as 1911. Intraoperative transillumination of the small intestine and colon also is generally well known. See, e.g., Ambartsoumian, A., "Infrared Transillumination Gastroscopy," Gastrointestinal Endoscopy 1995:41(3):270-71. Illuminators for transilluminating internal organs or vessels have been used in the fields of urology and gastroentology. An illuminator placed in the urethra or esophagus facilitates laproscopic and cystoscopic procedures by illuminating these organs thus avoiding unwanted damage to the organs. See, e.g., U.S. Pat. No. 5,624,432 to Angelchik (describing the preferred use of an illuminated bougie for illuminating the esophagus). Transillumination has also been used to facilitate the proper intracorporeal placement of catheters. See, e.g., U.S. Pat. No. 5,370,640 to Kolff, which discloses the use of a fiberoptic stylet device for facilitating the intracorpoeal placement of a retrograde coronary sinus catheter into the coronary sinus of a heart of a patient.
Although illuminators are generally well known by those skilled in the art, they typically have application for diagnostic or therapeutic purposes. Examples of such devices include the illuminators disclosed in U.S. Pat. No. 5,169,395 to Narciso, Jr., U.S. Pat. No. 5,196,005 to Doiron et al., U.S. Pat. No. 5,269,777 to Doiron et al., U.S. Pat. No. 5,330,465 to Doiron et al., U.S. Pat. No. 5,441,497 to Narciso Jr., and U.S. Pat. No. 5,454,794 to Narciso, Jr. et al. The devices described in those patents generally have the ability to deliver light to luminal surfaces such as blood vessels and are typically used for the diagnosis and treatment of a variety of medical conditions, with particular application to performing photodynamic therapy (PDT) in the treatment of diseased tissue such as tumors, inducing hyperthermia, or performing both percutaneous and intraoperative phototherapy of cardiovascular disease. However, despite the fact that transillumination has long been known, the present invention is believed to be the first use of transillumination to facilitate CABG surgery by any one of the methods described below.